This invention relates to an inflatable packer for sealing an annular space in a wellbore about a supporting element to which the packer is attached.
An inflatable packer is a downhole tool which is inflatable with a fluid to seal off an annular space in the well, for example between the casing and the wellbore, or between a drill string or other retrievable tool and an outer well casing. Although not so limited, the packer of the invention is particularly suited for isolating zones within a well for such purposes as cementing, fracturing, treating, testing, preventing gas migration to the surface, and for gravel pack operations.
Inflatable packers normally include an elastomeric body within which is disposed or embedded a reinforcement sheath. A recognized problem with prior art packers has been the inability to securely anchor the reinforcing elements of the packer body to end sleeve members which couple the packer assembly to the casing, drill string or other downhole tool. Typically, the reinforcing elements have been clamped at their ends between tapered wedging surfaces. In some instances, the mechanical clamping has been augmented by use of epoxy adhesives along the interface between the reinforcement free ends and the wedging portions of the sleeve terminations. Other problems in practice include the tendency of the body of the packer to rupture or develop pinhole leaks, and the failure of the body to return substantially to its original uninflated configuration, after repeated inflation/deflation cycles. Examples of such prior art include U.S. Pat. Nos. 2,643,722 to Lynes et al., 2,872,230 to Desbrandes, 3,028,915 to Jennings, and 4,191,383 to Baker et al.
The subject invention has as its primary object the provision of a packer construction which not only overcomes such prior art problems but also withstands high internal inflation pressures and external differential pressures across the packer element, and also the provision of an improved means for anchoring the ends of the reinforcement to the end sleeves of the packer assembly.